The present invention relates to a safety device capable of detecting trouble in optical transmission fibers for a laser apparatus and particularly for a medical laser apparatus.
Heretofore, medical laser apparatuses producing a high power beam of laser light have been used conveniently with an endoscope for treatment of digestive organs or respiratory systems and generally for a surgical treatment. When an optical fiber or a bundle of fibers for transmitting such a beam of laser light of the laser apparatus are broken or their exit or incident end surfaces are damaged, a trouble-detecting device will detect the broken or damaged end surfaces and stop the continuation of the beam of laser light.
However, when the laser apparatus is used to treat a tumor in a urinary bladder, a physiological salt solution to cauterize the tumor is present. Thus, the reflectivity at the exit end surface of the single optical fiber or fibers will be vastly decreased because the surface or surfaces are immersed in the solution or in another liquid such as water. The result is that this reduction in reflectivity creates a false signal of a trouble state or condition and the false signal is detected to stop the operation of the laser apparatus in spite of the fact that the apparatus is operating in a normal condition.